The present invention relates to a multiple reservoir implantable pump that is programmable so as to allow for varying flow rates of active substances from each of the reservoirs to be delivered to a patient.
Implantable pumps have been well known and widely utilized for many years. Typically, pumps of this type are implanted into patients who require the delivery of medication or other fluids (hereinafter referred to as “active substances”) to specific areas of their body. For example, patients that are experiencing severe pain may require pain killers daily or multiple times per day. Absent the use of an implantable pump or the like, a patient of this type would be subjected to one or more painful injections of such active substances. In the case of pain associated with more remote areas of the body, such as the spine, these injections may be extremely difficult to administer and particularly painful for the patient. Furthermore, attempting to treat conditions such as this through oral or intravascular administration of an active substance often requires higher doses and may cause severe side effects. Therefore, it is widely recognized that utilizing an implantable pump may be beneficial to both a patient and the treating physician.
Many implantable pump designs have been proposed. For example, U.S. Pat. No. 4,969,873 (“the '873 Patent”), the disclosure of which is hereby incorporated by reference herein, teaches one such design. The '873 Patent is an example of a constant flow pump, which typically includes a housing having two chambers, a first chamber for holding the active substance to be administered to the patient, and a second chamber for holding a propellant. A flexible membrane separates the two chambers such that expansion of the propellant in the second chamber pushes the active substance out of the first chamber. This type of pump also typically includes an outlet opening connected to the first chamber on one end and a catheter or other delivery device for directing the active substance to the desired area of the body on the other, a replenishment opening for allowing refilling of the first chamber, and a bolus opening for allowing the direct introduction of an active substance through the catheter without introduction into the first chamber. Both the replenishment and bolus openings are covered by septa that allow a needle or similar device to be passed therethrough, but which seal the openings upon removal of the needle. As pumps of this type provide a constant flow of active substance to the specific area of the body, they must be refilled periodically with a proper concentration of active substance suited for extended release.
Implantable pumps may also be of the programmable type, meaning that they can provide variable flow rates of an active substance therefrom. While these types of programmable pumps have typically involved the use of a solenoid pump or peristaltic pump, certain pumps similar to the above-discussed constant flow pumps have been modified in order to provide the ability of providing varying flow rates of an active substance from the pump. For instance, U.S. Patent Application Publication Nos. 2007/0005044 and 2007/0112328, the disclosures of which are hereby incorporated by reference herein, teach such pumps. However, those pumps are limited to a single active substance chamber.
Implantable pumps having multiple reservoirs are also known in the art. For instance, U.S. Patent Application Publication No. 2006/0271022 (“the '022 Publication”), the disclosure of which is hereby incorporated by reference herein, teaches a multiple reservoir pump design. While that reference also teaches such a multiple reservoir implantable pump that employs a patient controlled actuation mechanism, as well as a method of varying flow rate from the pump by modifying the amounts of active substance included in each of its multiple reservoirs (to allow multiple fixed flow rates), it does not teach a programmable type pump. The benefits of such a programmable pump are widely known from the previous incarnations that included a single active substance chamber. However, heretofore, there have not been any suitable incarnations of such a pump.
Therefore, there exists a need for a programmable multiple reservoir implantable pump.